The invention concerns a multiple spline hub, particularly for use on a telescopic shaft. The hub has a thin-walled tube section which is developed by means of cold-rolling as a toothed profile tube. It also has a connecting element, for instance a flange, a joint fork or the like, to which the toothed profile tube is connected.
German Petty Patent (Gebrauchsmuster) No. 1,911,806 shows a multiple-spline hub for a telescopic shaft. The hub is a part of a cardan shaft. The hub comprises a toothed-profile tube, which is fastened at a non-profiled end region to a joint fork. The toothed profile tube is manufactured starting with a tube of circular cross-section, and the profile is formed in the tube from the outside to the inside by drawing or pressing.
Apparently because of the above-described method of manufacture, the profile of the teeth in the known multiple-spline hub is rather large, as compared with the diameter of the hub. Accordingly, the number of teeth is small. The tooth heads are also quite rounded.
In a similar known multiple-spline hub, the toothed profile tube has a smaller pitch and accordingly has a larger number of teeth. In addition, there is a more desirable trapezoidal tooth profile. The toothed-profile tube is produced here by the cold-rolling of a thin-walled tube. For this purpose, the tube is placed on a profile mandrel. In this known multiple-spline hub, the torque carrying capacity is probably higher than in the case of the first mentioned hub embodiment. Furthermore, the method of manufacture of this toothed-profile tube in mass production is rather favorable both with respect to precision and with respect to cost. The level of torque which can be transmitted with this known construction is, however, still too small for many applications. The difficulty resides in the fact that manufacturing the toothed profile tube by cold rolling makes it necessary to start with a tube of only very slight wall thickness of, for instance, 1.5 to 2 mm.
For these reasons it has been necessary to manufacture those multiple-spline hubs which are to be capable of withstanding heavy loads by means of other traditional methods, such as producing the inner toothing of the hub by machining processes, for instance, slotting or reaming of the hub.